Copper minerals

Copper minerals are a group of minerals, which contain the copper element in their chemical composition. Here are some important copper minerals;

(1). Azurite: Cu3(CO3)2(OH)2

Physical Properties:

• Crystal System: monoclinic
• Cleavage: Perfect prismatic cleavage
• Hardness: 3.5 – 4.
• Specific Gravity: 3.77
• Lustre: Vitreous
• Colour: Azure-blue
• Streak: pale-blue
• Habit: Crystalline. Also in radiating groups or massive.

Occurrence: 

It occurs as a secondary mineral. It frequently alters to malachite.

Uses of Azurite: 

• Azurite having a shining blue colour, is used in jewellery, beads and ornamental stone.
• Azurite is used as an ore of copper.

(2). Malachite: Cu₂(CO₃)(OH)₂

Physical Properties: 

• Crystal Systems: monoclinic
• Cleavage: perfect but rarely seen
• Hardness: 3.5 – 4
• Sp.Gr: 3.9 -4.03
• Lustre: vitreous in crystals, silky in fibrous varieties and dull in massive varieties.
• Colours: Bright green
• Streak: pale green
• Habit: Usually in radiating fibres forming botryoidal or stalactitic masses. Also granular or earthy.

Occurrence: Malachite is a secondary copper mineral found in the zone of oxidation of copper veins.

Uses of Malachite: 

• Malachite is used as an ore of copper.
• Used as gemstone, and in jewellery.
• Used in small sculptures.
• Being green in colour, malachite is used as a pigment.

(3). Cuprite: Cu2 O

Physical Properties: 

• Crystal Systems: cubic
• Cleavage: poor cleavage
• Fracture: uneven
• Hardness: 3.5 – 4
• Lustre of Cuprite: metallic
• Colours of Cuprite: copper red, tarnishing to purple iridescent.
• Streak: grayish black.
• Habit of cuprite: usually massive

Occurrence: 

Cuprite is found in the upper oxidized portions of copper veins. It is often associated with native copper, malachite and azurite. 

Uses of Cuprite:

• Cuprite is used as an important ore of copper.
• Cuprite crystals are transparent to translucent and red to a deep red that can appear almost black. For jewellery, cuprite is mostly used as cabochons and beads.
• Cuprite is used as a colorant to produce ruby red glass.

(4). Bornite: Cu₅FeS₄

Physical Properties of Bornite:

• Crystals Systems: cubic
• Cleavage of bornite: absent
• Fracture: Uneven
• Hardness: 3
• Sp. Gr. 5.06 -5.08
• Lustre: metallic
• Colour: copper red, tarnishing to purple iridescent.
• Streak: greyish black.
• Habit: usually massive

Occurrence of Bornite:

Bornite is commonly found in hydrothermal ore deposits.

Uses of Bornite: 

• Bornite is used as copper ore.
• Metaphysically bornite is said to bring good luck and joy to life.
• Bornite is used as an eye-catching piece in homes, offices, and other places.
• Being too soft, bornite is not used in jewellery.
• It contains iron in its chemical composition, therefore, it may be used as iron ore.
• Bornite can give Cupric Sulfide on dissolving in Sulfuric acid.

(5). Chalcopyrite: CuFeS2

Physical properties of Chalcopyrite:

• Crystal System of Chalcopyrite: tetragonal crystal system
• Cleavage of Chalcopyrite: poor cleavage
• Fracture: uneven
• Hardness of Chalcopyrite: 3.5 -4
• Sp.Gr. of Chalcopyrite: 4.28
• Lustre of Chalcopyrite: metallic
• Colours: brass yellow.
• Streak of Chalcopyrite: greenish black
• Habit: Crystals show tetrahedral shape. Also massive and compact.

Occurrence: 

Chalcopyrite is the commonest copper mineral. It is found in hydrothermal veins. It is associated with pyrite and other sulfides.

Uses of Chalcopyrite: 

• Chalcopyrite, while containing copper and iron, is used as an ore of iron and copper.
• Some deposits of chalcopyrite contain zinc.
• Some chalcopyrite contains a sufficient amount of gold and silver.

(6). Chalcocite: Cu2 S

Physical Properties of Chalcocite:

• Crystal System: orthorhombic
• Cleavage of Chalcocite: poor
• Fracture of Chalcocite: Chalcopyrite has conchoidal fracture.
• Hardness: 2.2 – 3.0 on Moh’s scale
• Specific Gravity: 5.77
• Lustre: metallic
• Colour and streak: dark grey.
• Habit: Short prismatic crystals. Also massive

Occurrence:

Chalcocite is formed by the alteration of primary copper sulfides in zones of secondary enrichment.

Uses of Chalcocite: 

• Chalcocite is an important source of copper and iron because extracting the copper from the sulfur in Chalcocite is relatively easy.

(6). Covellite: CuS

Physical Properties of Covellite:

• Crystal System: hexagonal crystal systems
• Cleavage: perfect giving flexible plates.
• Hardness: 1.1 -2.
• Sp.Gr. 4.6 -4.76
• Lustre: metallic, massive varieties dull.
• Colour: indigo blue
• Streak: dark gray, shining
• Habit: platy crystals usually massive.

Occurrence: 

Covellite is found in the zone of sulfide enrichment. It is associated with other copper minerals, such as chalcocite, chalcopyrite, bornite, etc.

Uses of Covellite:

Covellite is used as an important ore of copper.

Related Articles:

1. Minerals of Silica Group
2. Minerals of Pyroxene Group
3. Minerals of Amphibole Group
4. Minerals of Mica Group
5. Minerals of Olivine Group
6. Minerals of Garnet Group
7. Minerals of Chlorite Group
8. Minerals of Clay Group
9. Minerals of Serpentine Group
10. Polymorphs/ Minerals of Al₂SiO₅
11. Calcium Minerlas
12. Aluminium Minerals
13. Iron Minerals
14. Manganese Minerals